I have created a custom NewDocSet.aspx form for my Document Set and am trying to use the SPCascadeDropdowns to work. I've got them working fine in the EditForm.aspx as that lives within the list's forms. However the NewDocSet.aspx lives in the _Layouts folder
so isn't within the lists context.

The error I get is: SCRIPT5009: 'childColumnStatic' is undefined | jquery.SPServices-0.7.2.js, line 1357 character 3

I had a look at the discussion
https://spservices.codeplex.com/discussions/405545 and it mentioned that this should be possible by adding a direct link to the List by changing the default listName: $().SPServices.SPListNameFromUrl(). Unfortunately I can't seem to get this working.

I'm also using the Guid of the Relationship List. As mentioned this is working fine for the standard Edit Form, just not for the NewDocSet Form.

Does anyone have any ideas on what I should put for the listName parameter, or how else I can achieve this?